1. Field of the Invention
The present invention relates to a holding mechanism for holding an image recording medium which is to be removably stored in an image processing apparatus.
2. Description of the Related Art
There is known a radiation image information recording and reading apparatus in which the radiation image information of a subject is recorded on a stimulable phosphor sheet positioned in a recording position, and thereafter stimulating light is applied in a main direction to the stimulable phosphor sheet and light emitted from the stimulable phosphor sheet in response to the applied stimulating light is read by a reading unit that moves in a direction substantially perpendicular to the main direction (see Japanese laid-open patent publication No. 2003-163092).
The stimulable phosphor sheet is a sheet which, when exposed to an applied radiation (X-rays, α-rays, β-rays, γ-rays, electron beams, ultraviolet radiation, or the like), stores a part of the energy of the radiation, and, when subsequently exposed to applied stimulating light such as visible light, emits light in proportion to the intensity of the stored energy of the radiation.
Since the stimulable phosphor sheet can repeatedly be used by erasing the recorded radiation image information, it is fixedly stored in the radiation image information recording and reading apparatus.
Though the stimulable phosphor sheet can be reused, it needs to be replaced with a new one because its sensitivity varies due to repeated exposures and aging. In addition, the stimulable phosphor sheet may also need to be replaced with a stimulable phosphor sheet having different characteristics depending on the purpose for which an image is to be captured on the stimulable phosphor sheet and the region which is to be imaged.
Inasmuch as the stimulable phosphor sheet is not replaced too frequently in the conventional radiation image information recording and reading apparatus, the stimulable phosphor sheet is normally fastened to a sheet holder in the apparatus by screws. When the stimulable phosphor sheet is to be replaced, the screws are removed to unfasten the stimulable phosphor sheet.
However, when the temperature in the radiation image information recording and reading apparatus varies, components of the sheet holder are expanded or contracted, tending to deform the stimulable phosphor sheet that is held by the sheet holder. As a result, radiation image information may not be recorded on or read from the stimulable phosphor sheet highly accurately.
Another problem is that because the stimulable phosphor sheet is relatively heavy, it may accidentally fall off when the screws are removed, and may possibly be damaged.